Production line constructing system

ABSTRACT

A production line constructing system for constructing a production line having groups of processing apparatuses, articulated robots for loading workpieces on and unloading processed workpieces from the processing apparatuses, and an automatic conveyor in the form of a vehicle for carrying a respective articulated robot and for conveying the workpieces between the processing apparatuses. The dimensions of the articulated robot are determined taking into consideration the width of passages in a work area, the dimensions of the vehicle, restrictions on available power supply, and the conveying speed of the vehicle carrying the articulated robot relative to the conveying speed of the operator. The production line is constructed so that a maximum loading/unloading area on the processing apparatuses within which a workpiece is loaded on and unloaded from the processing apparatus is included in a range of movement of the end effector of the articulated robot which is limited in dimensions.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This is a continuation of U.S. application Ser. No. 09/548,278, filed Apr. 12, 2000, which is a continuation of U.S. application Ser. No. 09/397,004, filed Sep. 15, 1999, now abandoned, which is a continuation of U.S. application Ser. No. 09/121,592, filed Jul. 24, 1998, now abandoned, which is a continuation of U.S. application Ser. No. 08/499,441, filed Jul. 6, 1995, now abandoned, the subject matter of which is incorporated by reference herein.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to a production line for article manufacture and handling.

[0003] Production line systems are disclosed in “FA technique for semiconductor”, Mitsubishi Electric Technical Bulletin, 11 (1989), “FA for semiconductor factory having complicated and variable manufacturing processes”, JMA PRODUCTION MANAGEMENT (July, 1990), Japanese Patent Publication (Kokoku) No. 64-6540 and Japanese Patent Laid-open (Kokai) Nos. 63-57158 and 2-117512.

[0004] Although those known systems relate to automated production lines in semiconductor production factories, nothing particular is considered about the relation between articulated robots, for loading workpieces on and unloading processed workpieces from apparatuses installed in a semiconductor production factory, and a processing apparatus group including a plurality of processing apparatuses. Further, there is still room in those known systems for improvement in the workpiece carrying robots, in the reduction of the space requirements for article carrying paths, and in the workpiece carrying speeds in the production line.

SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to provide a system forming an inexpensive automated production line that does not require excessively large workpiece carrying robots, which allows for high-speed carrying of workpieces, which reduces space requirements for carrying workpieces, and which uses standardized production equipment.

[0006] With the foregoing object in view, the present invention provides a system forming a production line comprising a processing apparatus group including a plurality of processing apparatuses, articulated robots for loading workpieces on and unloading processed workpieces from the processing apparatuses, and automatic carrying means for transferring workpieces between the processing apparatuses, wherein a maximum loading/unloading area among loading/unloading areas necessary for loading workpieces on and unloading processed workpieces from the processing apparatuses is included in the operating range of each articulated robot.

[0007] Since the present invention forms a production line in which the maximum loading/unloading area for each processing apparatus is included in the operating range of each articulated robot, the workpiece carrying robot need not be excessively large, the required workpiece carrying space can be reduced, the production equipment can be standardized and the workpiece carrying speed can be enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in connection with the accompanying drawings, in which:

[0009]FIG. 1 is a perspective view of a production line forming a system representing a preferred embodiment according to the present invention;

[0010]FIG. 2 is a diagram for explaining a desired range for standardization of facilities;

[0011]FIG. 3 is a front view of a robot, showing the dimensions of the robot;

[0012]FIG. 4 is a right side view of the robot of FIG. 3, showing ranges in which the robot wrist of the robot must be able to be positioned;

[0013]FIG. 5 is a top plan view of the robot of FIG. 3, showing the robot wrist at a maximum distance;

[0014]FIG. 6 is a diagram for explaining the moving range of the robot wrist of the robot of FIG. 3; and

[0015]FIG. 7 is a diagrammatic view showing symbols respectively representing positions in which cassettes are to be placed in loading/unloading areas for processing apparatuses.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016]FIG. 1 is a general layout of a production line forming a system representing a preferred embodiment according to the present invention. Generally, when producing semiconductor devices, wafers are fed to a production line, circuit forming processes and film forming processes are repeated to fabricate devices on the wafers, the wafers carrying the devices are inspected and tested, nondefective dies are cut out from the wafers, the nondefective dies are assembled and packaged to obtain semiconductor packages, the semiconductor packages are inspected and tested, and then nondefective packages are shipped.

[0017] Usually, a cassette containing the wafers is transported from the manufacturer to the factory by a truck, the cassette is cleaned to remove foreign matter which may have adhered thereto when the cassettes were exposed to the atmosphere, the cleaned cassettes are carried to a plant office 14 on, for example, the second floor, the wafers are put in an office stocker 13, and then the wafers are conveyed automatically by a lift 6 from the office stocker 13 to a line stocker 12 for temporary storage. When requested, the wafers are delivered from the line stocker 12 to a surface oxidation process, the surface-oxidized wafers are lotted out, lot numbers are assigned to a plurality of lots of wafers for daily production, each lot of wafers is put in a case, and the cases containing wafers are stored. In some cases, wafers are lotted out at stockers 1 or wafers are taken out by the operator from the line stocker 12 and processed wafers are put in the line stocker 12 by the operator.

[0018] Most semiconductor production lines are part of a job-shop production system including facility groups having the same functions. For example, a production line is formed by arranging a job area 11 requiring high cleanliness, stockers 1, area robots 9 and work areas 11′ and by separating areas by fire walls 10, as shown in FIG. 1, in conformity with fire laws. To separate those areas perfectly in case of fire, the fire walls are formed so as to be able to shut off laminar layers formed over and under the floor to maintain the cleanliness of the air, and interprocess conveyor rails 2 extending between work stations and working passages, quickly. A closed passage is formed between the work areas 11′ by arranging the conveyor rails 2 and a slewing device 5, and dollies 3 travel along the closed passage to convey workpieces automatically. When conveying the workpieces, a conveyor controller 7 controls the conveying operation for efficient conveyance according to requests for conveyance. The vehicle 3 that has arrived at a destination is moved to the entrance of the stocker 1, and then the workpieces are stored in the stocker 1.

[0019] In the production line, the workpieces are lotted out and conveyed along an in-passage conveying system, including the interprocess conveyor rails 2 extending between work stations and the slewing device 5, to a specified stocker 1 and are stored in the specified stocker 1. The workpieces are conveyed to a designated processing facility 8 by an in-area robot 9, i.e., an in-area conveying system, when requested. After the workpieces have been processed by the designated processing facility, the processed workpieces are returned by the in-area conveying system to the stocker 1, and then the workpieces are conveyed by the in-passage conveying system or by a through-port stocker 15 capable of transferring the workpieces therein from one to the next process, to the stocker of the next working area. Then, the same procedure is repeated in the next working area and, finally, the workpieces are stored in the stocker 1 of the final working area. In the final working area, the workpieces are conveyed by the in-area conveying system and processed by the facilities of the final working area, and then the workpieces are returned to the stocker 1. The workpieces are conveyed by the in-passage conveying system to the line stocker 12, and the workpieces then are conveyed into the office stocker 13 for storage. The workpieces are taken out from the office stocker 13 and are sent to an inspection work station for inspection.

[0020] Since the conveying systems are distributed, the steps of the automated production line can be sequenced, and the time necessary for developing the production line is shorter than the time necessary for developing a full-line automated production line. Therefore, the work areas 11′ may be either automated areas or manually operated areas.

[0021] Features of the production line system in accordance with the present invention will be described hereinafter.

[0022]FIG. 2 shows the distribution of the positions of the cassette 25 of the loader/unloader 26 of an apparatus 27 shown in FIG. 3 and included in the conventional semiconductor production line, represented by the height of the bottom surface of the cassette 25 from the floor surface and the depth of the front surface of the cassette 25 from the front surface of the apparatus 27, and the distribution of the attitudes of the cassette 25. In FIG. 2, the coordinates indicating the position of each of the arrows represent the position of the cassette 25 of each of the apparatuses 27, and the arrows, i.e., blank arrows and solid arrows, and the directions of the arrows indicate the attitude, i.e., vertical position or horizontal position, and the orientation, i.e., the angle between the reference axis of the cassette 25 and a datum line shown in FIG. 7, of the cassette 25 of each apparatus 27.

[0023] The positions of the cassette of the conventional apparatus are distributed in a wide range because the position of the cassette is determined for manual conveying. Therefore, an articulated robot on a vehicle is used for conveying the cassette, the articulated robot needs a comparatively long robot arm. A cassette carrying robot 9 travels along a passage between a group of apparatuses 8 arranged in opposite arrays in the work area 11 as shown in FIG. 1. The width of the passage is determined by taking into consideration requirements for the reduction of the width of the passage to the largest possible extent while still providing efficient use of the floor space of the clean room, sufficient space for the passage of operators, and for carrying the apparatuses in and out of the clean room. In this embodiment, the width of the passage is 1800 mm. Since the passage must allow a plurality of vehicles to pass each other, there are restrictions on the size of the vehicles carrying the articulated robots, and hence there are restrictions on the size of the articulated robots. If an articulated robot provided with a robot arm having a length which is comparatively large, as compared with the size of the vehicle, is used, the traveling speed of the robot is reduced and it takes a long time for conveying the cassette due to a weight limit (400 kg or below) and a power supply limit (1500 W or below). Thus, the production efficiency when the robot is used for conveying the workpieces is lower than that when workpieces are carried by operators.

[0024] Accordingly, a target range of the position of the cassette for the standardization of the facilities is determined as shown in FIG. 2, in order that the robot is able to reach the cassette on the loader/unloader of the apparatus and the robot is able to travel at a traveling speed higher than the carrying speed of an operator, even if the robot is comparatively small, i.e., when the robot is provided with a comparatively short robot arm, the robot is carried by a vehicle of a size fitting the size of the passage, and the automated production line is constructed using only standardized apparatuses. The positional range of the cassette is specified by a height range of 750 to 1150 mm and a depth range of 0 to 370 mm. A method of determining the dimensions of a traveling robot capable of reaching a cassette at the maximum depth in the positional range will be described hereinafter.

[0025] As shown in FIG. 3, a traveling robot is constructed by setting a six-axis or five-axis vertical articulated robot arm 22, provided with a robot hand 24 capable of holding a cassette 25, on a vehicle 21.

[0026] (1) Dimensions of the Robot Hand

[0027] The robot hand 24 for holding a cassette must be arranged so that the distance between the center of a robot wrist 29 and the cassette 25 is reduced to the greatest possible extent so that the torque necessary for moving the robot, which bears bearing the weight of the cassette, is reduced, and the robot must be lightweight. The horizontal distance between the center of the robot wrist 29 and the cassette 25 must be determined so that the robot hand 24 is able to reach a cassette 25 carried on a loader/unloader 26 and disposed in the depth of a lateral hollow 39, with the robot wrist 29 positioned outside the lateral hollow 39, as shown in FIG. 3. Therefore, it was determined that the height of the robot wrist from the bottom surface of the cassette should be 370 mm, and the horizontal distance between the front surface of the cassette and the robot wrist should be 210 mm.

[0028] (2) Range of Movement of Robot Wrist on Coordinate System on the Apparatus

[0029] When gripping the cassette 25 with the robot hand 24 of the robot 22, the robot hand 24 can be moved in any angular direction in the range of 0° to 360° However, to use the dimensions of the robot hand effectively to reduce the dimensions of the robot to the greatest possible extent when gripping a cassette carried in the depth of the apparatus, the robot wrist 29 should be set in front of the cassette 25 at a position of six o'clock. Thus, the positional range of the robot wrist can be determined by translating the positional range of the cassette shown in FIG. 2 by distances corresponding to the dimensions of the robot hand.

[0030] As shown in FIG. 4, the height of the position of the robot wrist 29 is in the range of 1120 to 1520 mm, i.e., the sum of the range of 750 to 1150 mm of the height of the bottom of the cassette and the height of 370 mm of the robot hand, and the range of the depth of the robot wrist is −210 to 160 mm, i.e., the remainder of subtraction of the depth of 210 mm of the robot hand from the range of 0 to 370 mm of the depth of the cassette.

[0031] (3) Distance between Robot and Apparatus

[0032] As shown in FIG. 4, even a comparatively small robot is able to grip a cassette placed in the depth of the apparatus when the distance between the center axis 30 of the revolving shaft (first shaft) of the robot and the front surface 31 of the apparatus 27 is small. The distance between the center axis 30 and the front surface 31 of the apparatus 27 is 400 mm at a minimum, which is the sum of the half width of 300 mm of the vehicle 21, the projection of 30 mm of a bumper from the side surface of the vehicle 21, the allowable error of 30 mm in positioning the vehicle and an allowance of 40 mm. The horizontal distance between the center axis 30 of the revolving shaft of the robot and the center of the robot wrist 30 is in the range of 190 to 560 mm, which is the sum of the range of −210 to 160 mm of the depth of the robot wrist and the distance of 400 mm between the center axis 30 and the front surface of the apparatus 27.

[0033] (4) Width of Arrangement of Cassettes

[0034] In most cases, a plurality of cassettes are arranged on the apparatus for efficient processing. The cassettes can be efficiently conveyed when the cassettes are conveyed with the vehicle held at one position. However, if it is desired to convey the plurality of cassettes with the vehicle held at one position, the distance between the center axis of the revolving shaft of the robot and the robot wrist must be increased.

[0035] If four cassettes 25 at a maximum are to be arranged laterally at a pitch of 300 mm as shown in FIG. 5, the distance between the respective center axes of the cassette at the opposite ends of the arrangement is 900 mm at a maximum.

[0036] (5) Range of Movement of Robot Wrist on Coordinate System on Robot

[0037] If the robot is located with the center axis of the revolving shaft of the robot 22 at a position corresponding to the middle of the arrangement of the cassette 25, as shown in FIG. 5, so that the robot hand is able to reach the cassettes 25 at the opposite ends of the arrangement, the lateral distance between the center axis 30 of the revolving shaft of the robot and the position of the robot wrist reaching to a cassette at one opposite end of the arrangement of the cassettes 25 is 450 mm, which is half the distance of 900 mm between the respective center axes of the cassettes 25 at the opposite ends of the arrangement of the cassettes 25. The distance along a direction perpendicular to the lateral direction between the center axis 30 and the robot hand is 560 mm at a maximum as mentioned in section (3). The distance between the center axis 30 of the revolving shaft of the robot and the position of the robot wrist is 718 mm, which is the square root of the sum of 4502 and 5602.

[0038] As shown in FIG. 6, the rectangular range 32 of the position of the robot wrist in a plane including the center axis 30 of the revolving shaft of the robot and the robot wrist 29 is defined by a lower limit of 1120 mm as mentioned in section (2), an upper limit of 1550 mm, which is the sum of the upper limit of 1520 mm of the range mentioned in section (2) and a lift of 30 mm necessary for removing the cassette from a cassette positioning guide 33, a minimum horizontal distance of 190 mm as mentioned in section (3) and a maximum horizontal distance of 718 mm.

[0039] (6) Dimensions of Robot and Operating Range of Robot Wrist

[0040] As shown in FIG. 3, the height L1 of a second axis 34 of the robot is 1300 mm, the length L2 of the robot upper arm 35, i.e., the distance between the second axis and a third axis, is 400 mm, and the length L3 of the robot forearm 36, i.e., the distance between the third axis and the axis of turning of the robot wrist, is 410 mm. The angular range θ2 of turning of the robot upper arm about the second axis is −90° to 90°, the angular range θ3 of turning of the robot forearm about the third axis is 10° to 145°, and the angular range θ5 of turning of the robot hand about a fifth axis, i.e., a pitching axis, is −120° to 120°. The angular ranges of turning of the components about the first axis, a fourth axis, i.e., a rolling axis, and a sixth axis, i.e., a yawing axis, are sufficiently large. The sixth axis 38, i.e., the axis of the extremity of the robot wrist, must be vertical when the robot hand operates to grip the cassette placed on the loader/unloader of the apparatus.

[0041]FIG. 6 shows the moving range 37 of the robot wrist, in which the lower boundary is the locus of the robot wrist when the robot upper arm 35 is fully turned forward, i.e., when the robot upper arm 35 is turned about the second axis to an angular position of 90°, and the robot forearm is turned about the third axis in its angular range of turning. The right-hand boundary is the locus of the robot wrist when the robot forearm 36 is turned to the angular position of 10° relative to the robot upper arm, and the robot upper arm is turned about the second axis in its angular range of turning. The upper boundary is the locus of the robot wrist when the fifth axis 38 is turned to the limit angular position of 120°, the robot forearm is held at 30° to a horizontal plane so that the sixth axis is in a vertical position, and the robot upper arm is turned in its angular range of turning. The left-hand boundary is the locus of the robot wrist when the robot forearm is turned to an angular position of 145° about the third axis relative to the robot upper arm, and the robot upper arm is turned in its angular range of turning. Although not shown in FIG. 6, there is a limit to the movement of the robot wrist on the left side to prevent interference of the robot wrist or the robot hand with the revolving shaft or the vehicle.

[0042] (7) Examination of the Moving Range

[0043] The cassette disposed in the depth of the apparatus, i.e., in the extreme right end as viewed in FIG. 6, is within the rectangular range 32 of movement of the robot wrist shown in FIG. 6, and there are an upper horizontal allowance of about 50 mm and a lower horizontal allowance of about 50 mm, which are approximately equal to each other. Therefore, the height L1=1300 mm of the second axis 34 of the robot is appropriate. The allowance of 50 mm, which exceeds the allowable error of 30 mm in positioning the vehicle, is appropriate. When the cassette is positioned at the front end of the apparatus, i.e., at the extreme left end as viewed in FIG. 6, the left boundary of a necessary range of turning of the robot wrist is on the left side of the boundary by about 60 mm of the left boundary of the possible range of turning of the robot wrist, and there are restrictions on the range of turning of the robot wrist to prevent interference of the robot wrist with the vehicle. Therefore, it is possible that the robot hand is unable to grip the cassette. Such a problem can be solved by increasing the distance of 400 mm between the first axis of the robot and the front surface of the apparatus to 600 mm to enable the robot hand to grip the cassette.

[0044] Although the supposed dimensions of the robot are set forth as appropriate in the foregoing description of the system, if the supposed dimensions are inappropriate, different dimensions of the robot are adopted and the ranges of movement of the robot wrist as mentioned in section (6) and section (7) are reexamined. Such a procedure is repeated until appropriate dimensions of the robot are determined.

[0045] An articulated robot having dimensions thus determined is set on a vehicle and is used for automatic conveying, and a production line is constructed by using only apparatuses having a loader/unloader capable of handling a cassette in the target range of position shown in FIG. 2 for standardized apparatuses so that the position of the cassette on each of the apparatuses of the production line is within the range of movement of the robot hand of a robot positioned in front of the apparatus.

[0046] According to the present invention, the use of a conveying robot of excessively large dimensions can be avoided, the workpieces can be conveyed at a high conveying speed, and the required space for conveying passages can be reduced. Furthermore, the production facilities can be standardized and an automated production line can be constructed at relatively low costs. 

What is claimed is:
 1. A production line constructing system for constructing a production line comprising groups of processing apparatuses, articulated robots having an end effector for loading workpieces on and unloading processed workpieces from the processing apparatuses, and an automatic conveying means for mounting a respective articulated robot thereon and for conveying the workpieces between the processing apparatuses, wherein a respective articulated robot is arranged with respect to a respective processing apparatus so that a maximum loading/unloading area on each of the processing apparatuses within which a workpiece is loaded on and unloaded from the processing apparatus is within a range of movement of the end effector of the articulated robot.
 2. A production line constructing system according to claim 1, wherein the articulated robot is dimensioned in accordance with an assumption that a plurality of the automatic conveying are able to pass each other on a passage formed between arrays of the processing apparatuses, the automatic conveying means and the length of the articulated robot arm being dimensioned taking into consideration a weight limit of the automatic conveying means and the mounted articulated robot thereof and a limit of available supply power for the automatic conveying means, so that a conveying speed of the articulated robot by the automatic conveying means is at least equal to a conveying speed of an operator.
 3. A production line comprising groups of processing apparatuses arranged so as to delimit a passage therebetween, articulated robots for loading workpieces on and unloading processed workpieces from the processing apparatuses, and a plurality of vehicles, a respective vehicle carrying a respective articulated robot for movement at least along the passage so as to at least enable conveying of the workpieces between the processing apparatuses, the production line being of compact size with the passage between the groups of processing apparatuses being of a minimum width dimension sufficient to permit movement of two vehicles carrying articulated robots adjacent one another at the minimum width dimension of the passage without interference therebetween, and the articulated robot having a range of movement of an end effector thereof which is limited in dimensions in correspondence with a maximum loading/unloading area of a respective processing apparatus so as to enable loading and unloading of a workpiece to and from the respective processing apparatus within the maximum loading/unloading area of the respective processing apparatus.
 4. A production line according to claim 3, wherein the maximum loading/unloading area of each processing apparatus is delimited by a height range of about 750 mm to about 1150 mm and a depth range of about 0 mm to about 370 mm.
 5. A production line according to claim 3, wherein the width dimension of the passage is no greater than about 1800 mm, the vehicle has a width of about 600 mm with a projection of a bumper of the vehicle from a side surface of the vehicle being about 30 mm, and the vehicle being positioned at a minimum distance from a front surface of a respective processing apparatus during a loading and unloading operation of the articulated robot carried thereby of about 400 mm as measured from a center line of the vehicle to the front surface of the processing apparatus.
 6. A production line according to claim 3, wherein the end effector of the articulated robot includes a robot wrist having a height position in a range of about 1120 mm to about 1520 mm and a range of depth of about −210 mm to about 160 mm.
 7. A production line according to claim 6, wherein the articulated robot has a revolving shaft positioned along a center line of the vehicle and a center axis of the revolving shaft being spaced from a center of the robot wrist within a range of about 190 mm to about 560 mm.
 8. A production line according to claim 3, wherein the vehicle and the associated robot have a combined weight no greater than 400 kg and a combined power supply requirement no greater than 1500 W, the vehicle enabling conveying of the workpieces between the processing apparatuses at a speed greater than the speed of an operator. 